Disk brake for elevator

ABSTRACT

A caliper brake set engages a disk on the machine shaft or drive sheave to hold the elevator car in place at a landing. The brake set is biased by one or a pair of springs to a &#34;brake-on&#34; condition, and a solenoid assembly is provided to hold the brake set in a &#34;brake off&#34; condition when power is supplied to the solenoid. Camming levers are used in conjunction with the solenoid to provide a mechanical advantage which allows use of smaller solenoids. The brake shoes are spring biased for improved operation on the disk.

.Iadd.This application is a reissue of 07/713,541, Jun. 7, 1991, U.S.Pat. No. 5,101,939, which is a continuation of Ser. No. 07/508,627,filed Apr. 13, 1990, now abandoned. .Iaddend.

TECHNICAL FIELD

This invention relates to an improved brake assembly for use in holdingan elevator car at a landing, which is also operable to stop the carunder emergency conditions, as in a power failure or overspeed. Moreparticularly, this invention relates to a caliper brake assembly forengagement with a disk secured to the elevator machine shaft or drivesheave to hold the latter against rotation.

BACKGROUND ART

Disk brakes which act upon a disk secured to an elevator machine shaftto hold the elevator car in place at landings are known in the priorart. The disk brakes in the prior art adapted for elevator use are fullplate disk brakes wherein the brake shoes are operable to engage theperiphery of the disk to hold the car in place. Full plate disk brakesmay be prone to dirt and moisture problems, and are not amenable tosolenoid stroke variations due to their mode of operation. They are alsonoisy due to the difficulty in controlling motion in the relativelyshort stroke of the flat faced armature.

DISCLOSURE OF THE INVENTION

This invention relates to a disk brake assembly for use in an elevatorsystem wherein the disk brakes are caliper-type-brakes which areoperative to engage a brake disk mounted on the machine shaft or drivesheave to hold the car in place at landings. More particularly, the diskbrake assembly of this invention obtains a mechanical advantage wherebysmaller solenoids can be used to hold the brake in an "off" condition.The larger stroke also provides the advantage of being able to controlthe noise of the plunger or core by stepping the solenoid plungers tobias the magnetic flux thus controlling the velocity and force of theplunger. The brake assembly of this invention is spring-biased "on", sothat when power to the solenoid is interrupted, the brake will engagethe brake . .drum.!. .Iadd.disk .Iaddend.by reason of spring action. Thespring action can be supplied to the brake shoes by a single spring, oreach brake shoe can be biased by its own individual spring. In thelatter case, if one spring fails the other will cause engagement of onebrake shoe with the disk which will be enough to hold the elevator at alanding safely. The brake assembly is modular whereby a number ofassemblies can be ganged on a single disk for heavier duty elevators.The construction of the brake is such that some of its components andits solenoid can be repaired or cleaned after being detached from theassembly while the brake shoes engage the brake disk. The brake shoesare each spring biased on their mounts so that they will not tilt anddrag on the brake disk when the brake is lifted.

It is therefore an object of this invention to provide an improved diskbrake assembly for use in an elevator system for holding the car inplace at landings and for emergency stopping of the car.

It is a further object of this invention to provide a brake assembly ofthe character described which is modular in construction.

It is another object of this invention to provide a brake assembly ofthe character described which includes a solenoid mechanism for liftingand holding the brake.

It is an additional object of the invention to provide a brake assemblyof the character described which can be repaired and cleaned with thebrake set holding the car in place.

It is yet another object of the invention to provide a brake assembly ofthe character described which includes individually spring-biased brakeshoes to obviate dragging of the shoes on the disk when the brake islifted.

These and other objects and advantages of the invention will become morereadily apparent from the following detailed description of a preferredembodiment thereof when taken in conjunction with the accompanyingdrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of two of the brake modules and anassociated disk which is keyed to the elevator machine shaft;

FIG. 2 is an elevational view partially in section showing the diskmounted on the sheave;

FIG. 3 is a top plan view of one of the brake modules;

FIG. 4 is a front elevational view of the solenoid operated brake latchportion of the assembly;

FIG. 5 is a view similar to FIG. 3 but showing the use of separateactuating springs for each brake arm; and

FIG. 6 is a fragmented sectional view of the lever-engaging pin on thebrake arms.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to FIG. 1, two identical brake modules 2 are shownoperably interacting with a brake disk 4 which is keyed to and rotateswith the shaft 6 (shown in phantom) of the elevator machine. Each module2 includes a brake assembly 8 and a brake latch assembly 10.

FIGS. 1 and 2 show details of the brake assembly 8. The brake assembly 8includes a bracket 12 which is fixed to the machine frame or stand 14(shown in phantom lines in FIGS. 1 and 2) and to which two opposed brakearms 16 are mounted for pivotal movement about vertical pins 22. Thepins 18 pass through lugs 17 on the brake shoes 20, which lugs 17 aredisposed above and below the brake arms 16. A brake shoe 20 is pivotallymounted on pins 22 to the brake arms 16 so as to flank the disk 4. Acoil spring 24 sandwiched between each brake shoe 20 and its respectivebrake arm 16 biases each brake shoe 20 about its respective pin 22 andagainst the inner end of an adjustable screw 23 threaded into each arm16, such that the brake pads 26 on the shoes 20 remain parallel to eachother and to the disk 4. In this manner the pads 26 are prevented fromdragging on the disk 4 when the brake is lifted. A brake actuatingspring 28 is mounted in spring caps 30 carried on spring guides 32 whichare secured to the brake arms 16. The spring 28 biases the arms 16outwardly about the pins 18 thereby biasing the brake shoes 20 againstthe disk 4. This action will occur whenever power is removed from thesolenoid 36. In the event of a power failure or an emergency, the brakewill automatically . .sit.!. .Iadd.set .Iaddend.on the disk. The spring28 thus supplies the force needed to set the brake. Cam pins 34 aremounted on the ends of the arms 16 distal of the brake shoes 20.

FIGS. 1 and 3 show details of the brake latching assembly 10. The latch10 includes a solenoid 36 containing an energizable coil, which solenoid36 is fixed to the machine stand 14 and a solenoid actuated plunger 38which moves up and down in the solenoid 36. Brackets 40 are mounted onopposite sides of the solenoid 36 and latch levers 42 with upturnedfingers 43 are pivotally mounted on the brackets 40 via pins 44. Aclevis 46 is disposed on the plunger 38 and receives overlapping ends 48of the levers 42. A pin 50 spans the clevis 46 and overlies the ends 48of the levers 42 thereby interconnecting the solenoid plunger 38 and thelevers 42. The upturned fingers 43 on the levers 42 engage the cam pins34 on the brake assembly 8.

It will be appreciated that when the latch levers 42 are disconnectedfrom the mount brackets 40, and released from the clevis 46 by removingpin 50, the core pin 38 can simply be pulled up out of the solenoid corefor cleaning or replacement.

When the solenoid 36 is supplied with electricity, the plunger 38 willbe recessed in the solenoid 36, and the clevis 46, levers 42 and campins 34 will be in the positions shown in solid lines in FIG. 4. The campins 34 will thus be latched causing compression of the brake actuatingspring 28 and lifting the brake shoes 20 off of the brake disk 4. Whenthe elevator car is properly leveled at a landing, the elevatorcontroller switches off electrical power to the solenoid 36 allowing theplunger 38 and clevis 46 to rise to the position shown in phantom linesin FIG. 4. This movement causes the levers 42 to pivot about the pins 44to the respective positions shown in phantom in FIG. 4 whereby theactuating spring 28 is able to pivot the brake arms 16 about the pins 18causing the brake shoe pads 26 to engage the disk 4. The enabling of theactuating spring 28 is the result of movement of the lever fingers 43away from the cam pins 34, as shown in phantom lines in FIG. 4. Thebrake will thus be set on the disk 4, and the car held at the landing.When it is desired to move the car away from the landing, the controllerswitches power back on to the solenoid 36. This causes the plunger 38 tobe drawn back into the solenoid 36 to return the clevis 46, levers 42and cam pins 34 back to the respective positions shown in solid lines inFIG. 4. Movement of the cam pins 34 causes the brake pads 26 to lift offof the disk 4, and compresses the actuating spring 28.

Referring to FIG. 6, details of the lever contact pin assembly 34 areshown. At the outer end of the brake arm 16, a threaded bore 17 isformed to receive an adjustment bolt 19 carrying a lock nut 21. The bore17 opens into a smooth bore 33 in which a pin 25 is slideably disposed.The pin 25 has rounded end walls . .27.!. .Iadd.37 .Iaddend.and . .29.!..Iadd.39 .Iaddend.and may carry a pair of friction rings 31 to snuglyhold the pin 25 in place within the bore 33.

In FIG. 5 there is shown an alternate embodiment of the inventionwherein two actuating springs 27 and 29 are used, one for independentlybiasing each of the levers 16. Each of the springs 27 and 29 seats on acentral plate 13 which is fastened to the bracket 12. By using twoseparate springs, if one fails, the other one will still be operable tomove one of the brake shoes against the disk 4 to provide some brakingof the car at the landing.

It will be appreciated that the brake assembly of this inventionprovides several advantages over the prior art caliper disk brakes.Biasing the brake shoes on the brake arms ensures that the brake shoeswill not drag on the disk when the brakes are applied or lifted, therebyquieting the brake. The use of levers in the latch assembly provides themechanical advantage sufficient to allow the use of a small latchsolenoid having a longer stroke. The longer stroke solenoid allows theuse of the stepped core whereby noise may be reduced. The use of twoactuating springs on the brake assembly assures that spring failure willnot completely prevent the brake from operating. The modularconstruction of the assembly enables one unit to be used in lighter dutyelevators, and multiple units to be used in heavier duty elevators. Italso allows repair and cleaning of the latch assembly components whilethe brake is set.

Since many changes and variations of the disclosed embodiments of theinvention may be made without departing from the inventive concept, itis not intended to limit the invention otherwise than as required by theappended claims.

What is claimed is:
 1. An elevator caliper disk brake assemblycomprising:(a) a pair of brake shoes pivotally mounted on vertical pinson an associated pair of horizontal brake arms, said brake shoes havingopposed planar vertical braking surfaces and said brake shoes having apair of horizontal lugs straddling said brake arms above and below thelatter; (b) horizontal spring means disposed between said brake arms forengaging said brake arms to bias said brake shoes toward each other; (c)a brake disk interposed between said brake shoes, said brake disk havingparallel opposite vertical side surfaces facing respective ones of saidbraking surfaces; (d) stop means on each of said brake arms forengagement with a respective one of said brake shoes to limit pivotalmovement of said brake shoes on said brake arms in one direction; (e)springs on each of said brake arms for biasing each of said brake shoesagainst its respective stop means, said stop means and said springsbeing operable to retain said braking surfaces substantially parallel tosaid side surfaces of said brake disk; and (f) latching meansincluding:(i) a pair of horizontal pivotally mounted levers forengagement with said brake arms to hold the latter against the bias ofsaid spring means; and (ii) solenoid latch actuating means including acylindrical solenoid plunger operably engaging said levers toselectively hold the latter against said brake arms, said plunger beingreciprocally vertically movable between latch-on and latch-off positionsto selectively latch and release said brake arms said solenoid plungerhaving a constant diameter and being telescoped into a conformingcylindrical passage in the solenoid whereby said solenoid plunger isfreely slidable in said passage and can be freely lifted out of saidpassage after disengagement from said levers.
 2. The brake assembly ofclaim 1 wherein said spring means comprises a pair of coil springs eachengaging one of said brake arms to independently bias said brake shoestoward each other.
 3. The brake assembly of claim 1 wherein saidsolenoid plunger is connected to adjacent ends of said levers with acommon connecting pin.
 4. The brake assembly of claim 3 wherein saidadjacent ends of said levers are overlapped.
 5. The brake assembly ofclaim 1 further comprising contact means for providing operating contactbetween said brake arms and said levers, said contact means comprisingcontact pins slideably mounted on ends of said brake arms distal of saidbrake shoes, and arranged for engagement with said levers, and means foradjustably moving said contact pins toward and away from said levers tomodify the positioning of said levers.
 6. The brake assembly of claim 5wherein said contact pins are provided with rounded ends engaging saidlevers for providing point contact between said brake arms and levers.7. The brake assembly of claim 1 wherein said stop means is adjustablewhereby the pivotal position of said brake shoes on said brake arms canbe varied. .Iadd.8. A brake unit for an elevator hoist apparatus for usewith an electric motor output shaft, comprising:a brake disc having twobraking surfaces and connected to the motor output shaft for rotationtherewith; a pair of brake arm assemblies each having a movable brakearm having a first end and second end and a brake shoe mounted on thefirst end of the brake arm, each of the brake arm assemblies beingmovably disposed in the vicinity of the brake disc for selective brakingengagement of the brake shoes with the braking surfaces of the brakedisc; brake spring means for biasing the brake shoes on the brake armstoward the braking surfaces; a pair of levers, each of which ispivotally supported on an axis perpendicular to the axis of the outputshaft, each of the levers having a first end and second end engageablewith the second end of one of the brake arms; and actuator means forengaging with the first ends of the levers and pivoting the levers abouttheir respective axis, thereby separating the brake shoes from the brakedisc against the force of the brake spring means. .Iaddend.